JP2578458B2 - Mixtures of chiral liquid crystal compounds and devices containing them - Google Patents

Abstract

Optically active compounds of formula (I), where X has a structure (II) and B is C1-12 alkyl, a chiral group or a group having a general structure (III), where R and R' are H, C1-12 alkyl, alkoxy, alkylcarbonyloxy, or alkoxycarbonyl, each ring (IV) and (V) is the same or different, A and D are single bonds or bridging groups, each a and d is 0 or 1; Z, Z' are CN, Cl, F, Br or CF3; provided when Z is CN or Cl, then when B is alkyl X-Y is not (VI) or (VII). Ferroelectric smectic liquid crystal mixtures containing these compounds are also described.

Description

The present invention relates to novel chiral compounds suitable for use in ferroelectric smectic liquid crystal mixtures, to such mixtures and to the devices containing them.

Ferroelectric smectic liquid crystal materials are chiral tilted smectic C, F, G, H, I, J and K
Phase (expressed as S ^* _C, etc., * indicates chirality)
Using the ferroelectric properties. S _C phase is the most generally useful for the most fluid, at temperatures above the chiral smectic phase in order to assist surface alignment in a liquid crystal device, the material may exhibit S _A or nematic (denoted N) phase Is particularly desirable. Ferroelectric liquid crystal material is low viscosity, S _C phase present in a wide temperature range including room temperature, it is desirable has a chemical and photochemical stability, in particular, spontaneous polarization coefficient measured at NCCM ^-2 ( spontaneous polarisation coefficient)
It is desirable that _PS is good. Such a material allows a liquid crystal display device to be switched very quickly.

Despite several single compounds exhibiting all of the desired properties outlined above, the ferroelectric smectic liquid crystal materials used today generally consist of a mixture of compounds that together exhibit a chiral gradient smectic phase. ing.
Some of the compounds in such mixtures, together or individually, exhibit a smectic phase (not necessarily a chiral smectic phase) of the type "smectic host"
Are those called, some of which improve the properties of the mixture, for example, an additive for suppressing undesirable smectic phases, one or more of those, ideally a good P _S is a mixture It is an optically active compound that makes it chiral smectic. Such optically active compounds are referred to by those skilled in the art as "chiral dopants".

PCT patent application WO 86/00087 describes a chiral group: Wherein X represents Cl, CN or CH ₃ , and R ₁ and R ₂ represent the residues of the molecule. All of the compounds described are phenyl-pyrimidine groups as mesogenic units. Is always contained. The pyrimidine ring is said to be particularly useful in the short molecules described. because,
This is because the molecular arrangement increases the intermolecular distance in the mass, and thus reduces the viscosity. In many compounds, and Is described. These two compounds do not, by themselves, exhibit a smectic phase.

PCT application WO87 / 05015 has the general formula Wherein X can be CN, halogen or CH ₃ ; R ¹ and R ²
Can be alkyl or alkoxy, Q ¹ , Q ² , Z ¹ and Z ² are linking groups, and A ¹ , A ² and A ³ are cyclic groups (such as phenyl). doing. X
No example of a compound in which X is CN is described, and it is stated that X is preferably halogen.

It is an object of the present invention to provide compounds having advantageous properties for use in ferroelectric smectic liquid crystal mixtures. Other objects and advantages of the present invention will become apparent from the following description.

According to a first aspect of the present invention, the following general formula I: [Wherein X is a general formula: (Wherein, R is hydrogen, C ₁ ~ ₁₂ alkyl or alkoxy, rings May be the same or different and each is independently selected from phenyl, halogen-substituted phenyl or trans-cyclohexyl, A is selected from a single bond, COO or OOC, and a is 0 or 1) , Y is selected from COO or 0, B is alkyl having 1 to 12 carbon atoms, cyclohexyl or (Where d is 0 or 1, R 'is hydrogen, C ₁ ~ ₁₂ alkyl or is selected from alkoxy) providing a group of optically active compound represented by the.

Many compounds of Formula I are useful as chiral dopants in ferroelectric smectic liquid crystal mixtures with host components.

Thus, in another aspect of the invention, there is provided a ferroelectric smectic liquid crystal mixture containing at least two compounds, at least one of which is a compound of formula I.

The relative utility of various Formula I compounds is one of the factors that determine the structure and other suitability discussed herein.
One.

In formula I, R is preferably alkyl or alkoxy having 1 to 20 carbon atoms, particularly preferably n-alkyl or alkoxy having 7 to 10 carbon atoms. Alkoxy is more preferred.

When -Y-CH (CN)-is present as -COO-CH (CN)-, it is particularly preferred that B is cyclohexyl or alkyl.

When B is alkyl, it may be n-alkyl, branched alkyl or optically active alkyl. Structure B 'when B is branched or optically active: Where t can be 0 or an integer from 1 to 6, and n and m can be the same or different and can be values from 1 to 6 at any point. Branching of the branched alkyl chains may occur. Preferably, t is 0 or 1,
At least one of n or m is 1.

Preferred alkyls from which B can be selected are listed in Table 1 below.

In Table 1, particularly preferred alkyl groups are underlined.

In particular, -Y-CH (CN)-is -COOCH (CN)-, and some examples of preferred X groups in Formula I having preferred B groups are shown in Table 2 below: [Wherein R is n-alkyl or n-alkoxy, especially those having 3 to 12 carbon atoms]. In these structures, 2.1 to 2.7 is preferable.

Some of the particularly preferred overall structures of the compounds of formula I are shown in Table 3 below: Wherein R ₁ is C ₃ -C ₁₂ n-alkyl or n-alkoxy; R ₂ is C ₁ -C ₁₂ n-alkyl or a branched or optically active alkyl group of structural formula B ′ And particularly those of the structural formulas shown in Table 1, and (F) indicates that a fluorine substituent may be present].

The chiral centers of the compounds of formula I may be of the (R) or (S) configuration, and when the compound has one or more chiral centers, it may be in a ferroelectric smectic mixture containing them. such as to form a S ^* phases with similar P _S is preferable.

Compounds of formula I wherein the unit -Y-CH (CN)-is COOCH (CN) can be prepared, for example, by the many widely applicable routes 1 to 5 shown schematically in Figs. . -Y-CH (C
Compounds of Formula I wherein N)-is -OCH (CN) may be prepared, for example, by Route 6 of FIG.

In paths 1-6, in some cases, the expression An α-hydroxycarboxylic acid of the formula: A group B is introduced into a compound of formula I using an α-amino acid of formula I.

Routes 1-6 are generally preferred, but especially where B is alkyl, phenyl or cyclohexyl.

Some of these acids are commercially available as optically pure optical enantiomers, for example, the hydroxycarboxylic acids lactic acid (B = CH ₃ ) and mandelic acid (B = phenyl), a series of commercially available or There are natural amino acids such as alanine, valine, leucine, isoleucine, butyline, alloisoleucine, norvaline, norleucine and phenylalanine. Because many of these acids are of biochemical origin, they are often obtained as one or more optically enantiomers, or enantiomers, and are therefore relatively inexpensively optically enantiomers. A pure product is obtained. Therefore, it is preferred to use these acids where possible.

Also, these acids can be synthesized to lead to a wider range of B groups. In fact, α-hydroxy acids can be prepared from the corresponding amino acids by reacting the amino acids with nitrous acid at low temperatures: (See, for example, "Tetrahedron" (1979), 35 , 1603 and JA
CS (1956) 78 , 2428).

Other methods for preparing α-hydroxycarboxylic acids are also known,
For example, the "Chemistry of C" cited 11 processes including those where B could be linear, branched or optically active alkyl.
arbon Compounds ”DH Dodd (pvb Elsevier) (195
2), IB , pp. 780-781 (Ref 1).

Similarly, a wide range of amino acids are synthesized, including, for example, those where B is linear, branched or optically active alkyl.
Amino acids having a suitable B group can be synthesized by general known methods such as those described in Ref 1 pp. 813-817, which describes various methods.

Thus, there is no difficulty for a competent chemist to make a suitable α-hydroxy or amino acid. These processes result in optical enantiomers or racemic mixtures of enantiomers, which can be degraded by known methods, for example using brucine or a stereospecific enzyme reaction.

When the amino acids used for the production of α-hydroxy acids, or for example used directly in Route 4, have a functional group in their side chain B, they can be used to change the structure of the group B.

For example, serine, threonine and tyrosine have-
It has an OH group, so that an ester or ether bond can be introduced. Aspartic acid and glutamic acid have a -COOH group in the side chain, which can also introduce esters or other bonds.

Examples of the types of units that can be introduced into compounds of formula I using amino acids with functional groups in the side chains include:

Similarly, in the following routes 1 to 6, the general formula RX-CO ₂ H
(Wherein X is as defined for formula I)
When it is necessary to use the carboxylic acids of formula (I), many of them are commercially available or prepared by well-known general methods such as, for example, hydrolysis of the corresponding cyano compound RX-CN. sell.

 The steps of each of the paths 1 to 6 are described below.

Route 1 Steps are shown below.

(1) (i) 20% aqueous solution of Cs ₂ CO ₃ or K ₂ CO ₃ , methanol-water (9: 1) pH 7.0 (ii) PhCH ₂ Br, DMF (2) N, N-dicyclohexylcarbodiimide (D
CC), 4- (N-pyrrolidino) pyridine (N-PPy), C
H ₂ Cl ₂ (3) 5% Pd / c, hydrogen, ethanol (4) (i) oxalyl chloride, benzene, dimethylformamide (DMF) (ii) Aqueous ammonia solution, diglyme (diglyme) (5) SOCl ₂ , DMF 4 - alkyl or alkoxy - although the description for use with 4'-carboxylic acid, route 1 is generally suitable for all acids of formula R-X-CO ₂ H, in particular bonded by single bonds Ring Suitable for groups X that include By using lactic acid in step (1), B becomes methyl, but other homologous α-hydroxycarboxylic acids can be used to make B another alkyl group. Mandelic acid, ie Can be used to convert B to phenyl.

Route 2 (1) Ethyl acetate, hydrogen chloride (2) KOH, ethanol, water (3) Same as steps (1) and (2) in route 1 (4) Oxalic acid, 99% ethanol aqueous solution (5) Same as step (2) in route 1 (6) Sequence of steps similar to steps (3)-(5) of Route 1 As with Route 1, this route generally applies to compounds of Formula I wherein one of the groups A in X is COO Can.
By using other α-hydroxy acids, a different group B can be introduced into the molecule as described above.

Route 3 (1) Hydrogen, 5% Ph / Al ₂ O ₃ , methanol (2) Same as Step (1) of Route 1 using methanol solvent (3) DCC, N-PPy, CH ₂ Cl ₂ (R = alkyl or alkoxy) (4) hydrogen, 5% Pd-c, ethanol (5) (i) (COCl) ₂ , benzene, DMF (ii) aqueous ammonia, diglyme (6) SOCl ₂ , DMF pathway 4 (1) Sodium nitrite, H ₂ SO ₄ (2) PhCH ₂ Br, DMF (Ph = phenyl) (3) DCC, N-PPy, CH ₂ Cl ₂ (4) H ₂ / Pd-c (5) oxalyl chloride, DMF; NH ₃ (6) SOCl ₂ , DMF Route 4 is shown where X is an R-biphenyl group, but in step (3) any suitable The method works equally well with carboxylic acids.

In route 4, group B in the starting amino acid is group B of the final product. The amino group may be used in any enantiomeric form (racemic amino acids yield racemic products). Residue B in the starting amino acid may itself have an asymmetric carbon atom, as in, for example, isoleucine.

Various other compounds wherein the unit -YWCH (Z) is -COOCH (CN)-are prepared via routes derived from Routes 1-4 above. For example, the compounds of structural formulas 3 and 4 can be obtained by esterifying the product of step 3 (2) with the acid prepared in step 2 (2), and the same route as in steps 2 (3) to 2 (6). Can be produced.

Compounds of structural formulas 3,5 are prepared via route 5 shown in FIG. 5, starting from commercially available biphenyl and bromobenzoic acid.

Route 5 (1) When F is present: n-BuLi, ether, -35
° C, 20 minutes, when ZnCl ₂ , THF, N ₂ F are not present: n-BuLi, ether, -5 ゜ to -10
° C., 45 min; ZnCl _2, THF, Nc (2) appropriate alcohol or phenol, for example, Step 4 (2) or the product of 3 (2), DCC, N -PPy, CH
₂ Cl ₂ (3) Pd [Ph ₃ P] ₂ Cl ₂ , diisobutylaluminum hydride, THF N ₂ By the same method as in Steps 4 (4) to 4 (6), the product of Step 5 (3) was purified. Can be converted to, for example, a cyano compound of structural formula 3.5.

Route 6 (1) Esterification of α-hydroxy acids, for example using the DCC method Some of such esters, for example, ethyl lactate, are commercially available.

(2) Toluene-4-sulfonyl chloride, pyridine (3) K ₂ CO _3, acetonitrile (4) KOH, ethanol, H ₂ O (5) and (6) Step 4 (5) and (6) the same formula I Can be used as an optically active component of a ferroelectric smectic liquid crystal mixture, that is, as a chiral dopant.

When the compounds of the formula I are used as components of such mixtures, the following advantages are obtained, in particular with the preferred compounds described above.

(I) They may exhibit a very high spontaneous polarization coefficient (P _S). This is the P of the mixture estimated to be 100% of the compound of formula I
Is _S, it is convenient may represent as the estimated P _S. This means that it is necessary to include very small amounts of the compound of formula I in the mixture.

(Ii) they can give rise to chiral smectic phases in mixtures having a very long helical pitch. This is determined by measuring the chiral nematic N ^* pitch induced when mixed with a nematic liquid crystal material.
It can be evaluated more conveniently. For some ferroelectric smectic liquid crystal devices, the pitch should be as close as possible to the spacing between the electrodes, and in practice the narrower the spacing between the electrodes, the more difficult it is to manufacture, so long pitches are desirable.

(Iii) Chiral smectic mixtures containing them may exhibit a S _C ^* phase that persists over a wide temperature range, including room temperature.

(Iv) they are compatible with many hosts and additives, for example:

(V) They may allow for very high switch speeds, which is advantageous for video screen type adaptations, for example.
This is because many known chiral dopants are viscous,
Partly due to (i) above in that the mixtures containing them are made viscous. The fact that a good _PS is obtained with the compounds of the formula I means that only relatively small amounts have to be used and therefore have little adverse effect on the viscosity.

(Vi) Since the starting amino acids for preparing them are commercially available in both D (+) and L (+) optical enantiomers, they are often in both enantiomeric forms. Compounds of formula I may be obtained. This allows
The inclusion of the oppositely twisted optical antipode of the compound of formula I in the mixture particularly facilitates the "compensation" of the pitch of the mixture containing them (see below).

The ferroelectric smectic liquid-crystal mixtures according to the invention contain at least one compound of the formula I. Typically, the mixture will contain from 1 to 20% by weight of the compound of formula I, for example about 10% or less. The P _S generally a mixture is proportional to the amount of presence to chiral dopants.

The mixture contains a compound showing a S _C phase individually or in together one or more. Such compounds are known as smectic hosts.

Many types of compounds are known that can be used as smectic hosts, and some examples of suitable types are given in Table 4. Among these compounds, compounds of Formula 4.1, 4.2, 4.3 and 4.8, in particular those in which the R ^A and R ^B includes each independently 5-10 carbon atoms preferred. It is particularly preferred to use two or more of the same type, for example homologs, for example to lower the melting point.

These preferred hosts, S _C mixture, in S _C phase and S _C or higher temperatures that exist over a wide temperature range including room temperature
Shows the _SA phase and can promote alignment of the liquid crystal material. Typically, the mixture will contain 40-99%, for example about 80%, of the host compound.

Wherein R ^A and R ^B are C _1-12 n-alkyl or n-alkoxy. The additives in such a mixture can serve many functions. One such function is the "pitch compensating substance"
Is as. “Pitch compensation” refers to the induction of a spiral smectic phase in the oppositely twisted direction.
One or more compounds are included in the ferroelectric smectic mixture. In such cases, the compound will unwind the helical phase induced by others. This can be used for the production of long pitch helical smectic phases, and the pitch of the mixture can be closely adjusted using the two compounds in appropriate adjusted amounts.

In the mixtures according to the invention, various compounds of formula I or optical enantiomers, for example compounds: By using oppositely twisted compounds of formula I as described above, which are of the L (+) and S (+) forms of the above, pitch compensation can be conveniently performed.

One or in addition also use other amides such as, for example, the amides described in PCT / GB87 / 00223 as shown in Table 6 or other optically active additives such as terphenyl described in UK patent application 8703103 The latter terphenyl is particularly suitable when the host contains one or more compounds of the formula 4.3.

Examples of these two types of pitch compensating materials include compounds: Wherein R and R ′ are independently C _1-12 n-alkyl or n-alkoxy. R 'is preferably CH _3. Many other pitch compensating additives will be apparent to those skilled in the art. For example, if the host is formula 4.1 or
4.2 of the compound when they include one or more suitable pitch compensation material may be a compound of formula 4.1 or 4.2 R ^B and / or R ^A is an optically active alkyl or alkoxy.

Using an additive to aid the appearance of S _A phase at a temperature above the temperature at which S ^* _C phase is present, in the aggregate used S ^* _C
Phase alignment can be assisted. Host mostly formula
When consisting of a compound of 4.1 or 4.2, preferred additives to achieve this are formulas: Wherein R and R ¹ are independently n-alkyl or n-alkoxy containing 1 to 12, especially 5 to 9 carbon atoms.

The additives also have the function of suppressing undesirable smectic phases, such as S _A or S _B , so that, if they do, they appear at a temperature as far as possible from the working temperature. A preferred class of additives that fulfill this function is of the formula: Wherein R and R ¹ are independently n-alkyl or n-alkoxy containing 1 to 12, especially 5 to 9 carbon atoms. Compounds of formula 4.8 can also be used as additives to control unwanted smectic phases in mixtures where they are not used as hosts.

Additives can also improve other properties of the mixture, such as increasing switch speed. The compound that does this is Containing a group, such as the general formula: Or [Wherein, R and R ¹ independently represent, in particular, 3 to 10 carbon atoms.
Alkyl groups].

For example, other known additives may be included to improve viscosity, melting point or other properties.

Typically, the mixtures according to the invention may contain 0 to 50% by weight of additives, preferably 0 to 20%. Very little pitch compensating material, for example less than 1% by weight of a tightly twisted compound 5.1 where R is C ₁₀ H ₂₁ and R ¹ is CH ₃ , and preferably less than about 10% by weight of 6,7, Compounds such as 8.1 or 8.2 may be required.

The mixtures of the present invention can be used in any of the known types of ferroelectric smectic liquid crystal devices, and devices containing such mixtures are another aspect of the present invention.

The present invention will now be described by way of example only with reference to the accompanying drawings. The accompanying drawings, first to sixth Figure: preparative routes Figure 7 of the present compounds: graph Figure 8 of P _S with respect to the temperature of the present invention, a mixture: shows a liquid crystal device.

Examples of the preparation of the compounds of formula I, ferroelectric smectic liquid crystal materials containing them and liquid crystal electro-optical displays using them are as follows.

Example 1 Using Route 1 Production of Step 1 (1) S-(+)-lactic acid (18
g) was dissolved in methanol (360 ml) and water (40 ml) was added. The solution was titrated to pH 7.0 with a 20% aqueous cesium carbonate solution. The solvent was removed at 50 ° C. under reduced pressure and the residue was re-evaporated twice from DMF (2 × 100 ml) at the same temperature. The resulting cesium salt of a white solid was stirred with benzyl bromide (34.2 g) in DMF (300 ml) for 15 hours. Next, CsBr was filtered off, the filtrate was concentrated, and ether was added to the residue (150 ml). Water (100 ml), saturated NaHCO ₃ (500 ml) and water (100 m
The organic phase was washed successively in l) and finally dried over (MgSO ₄ ). After removing the solvent, the remaining liquid was distilled under reduced pressure to obtain the product as a colorless liquid (yield 28.8 g; 80%)
bp 96 ° C / 0.05mmHg ▲ [α] ²⁴ _D ▼ -12.9 （Step 1 (2) Sieve-dried CH ₂ Cl ₂ (250 ml)
4-R-biphenyl-4'-carboxylic acid (10.8
g), S prepared in Step 1 (1) - (-) - benzyl easier stirred mixture of Tate (5.9 g) and N-PPy (0.49g), CH 2 Cl 2 (50ml) solution of obtained by sieve dried DDC
(7.5 g) The solution was added slowly. The mixture was stirred at room temperature for 5 hours. The N, N-dicyclohexylurea was filtered off, and water (100 ml), 5% acetic acid aqueous solution (100 ml), water (2 × 100 m
The filtrate was continuously washed in l) and finally dried (MgS
O ₄ ). After removing the solvent, silica gel and eluent (4:
1) Dichloromethane: A composition diester was purified by column chromatography using a petroleum fraction (bp 60 to 80 ° C). The product was recrystallized from ethanol.

The properties of the compound prepared in this way were as follows: R = C ₉ H ₁₉ mp 60.5 ° C .; 〔[α] ²⁴ _D ▼ + 21.6 ゜ R = C ₁₀ H ₂₁ O mp 85 ° C .; 〔[ α] ²⁴ _D ▼ + 24.2 ゜ R = C ₈ H ₁₇ O mp 62.5 ° C .; 〔[α] ²⁴ _D ▼ + 24.7 ゜ Step 1 (3) Step 1 (2) product (10-12 g) Was dissolved in ethyl acetate (150 ml). Add 5% Pb on charcoal (200mg)
The mixture was stirred overnight under a hydrogen atmosphere. After completing the hydrogenation (consuming 500 ml of hydrogen), the catalyst was filtered off and the filtrate was evaporated to dryness. The colorless solid residue was recrystallized from a petroleum fraction (bp 60-80 ° C) to give the carboxylic acid as colorless needles.

R = C ₉ H ₁₉ mp 106 ° C; ▲ [α] ²⁴ _D ▼ + 32.3 ゜ R = C ₁₀ H ₂₁ O mp 115 ° C; ▲ [α] ²⁴ _D ▼ + 35.0 ゜ R = C ₈ H ₁₇ O mp 126 ° C 〔[Α] ²⁴ _D ▼ + 40.8 ゜ Step 1 (4) Oxalyl chloride (0.02 mol) in sodium dried benzene (50 ml) and sieve drying of the carboxylic acid (0.01 mol) in step 1 (3) First, it was converted to acid chloride by reacting with DMF (3 drops) at room temperature for 3 hours. Distillation under reduced pressure removed excess oxalyl chloride and solvent. The crude acid chloride residue was dissolved in diglyme (20 ml) and then, with vigorous stirring, an aqueous ammonia solution (25 ml, d = 0.88) was added dropwise. After the addition, the reaction mixture was stirred for 1.5 hours at room temperature. Next, the reaction mixture was cooled with cold water (200 m
Diluted in l), the product was filtered off, washed with excess water and finally air-dried. The product is petroleum fraction (bp 80 ~
(100 ° C.) to give the amide as a white powder.

R = C ₉ H ₁₉ yield = 2.6 g (66%); mp 145 ° C. [α] ²⁴ _D ▼ + 48 ゜ R = C ₁₀ H ₂₁ O yield = 1.8 g (47%); C ₁ 130 C ₂ 143 I ▲ [α ²⁴ _D ▼ + 43.4 Step 1 (5) A mixture of redistilled thionyl chloride (0.063 mol) and sieve-dried DMF (10 ml) is combined with the product of step 1 (4) in DMF (30 ml) (0.0063 ml). ) Was added to the vigorously stirred solution. After the addition, the reaction mixture was stirred at room temperature for 2 hours, poured onto ice-water (200 ml) and the product was washed with ether (2 × 1).
00ml). Combine the ether extracts and add a saturated aqueous solution of sodium bicarbonate (2 × 100 ml), then water (100 ml)
And dried finally (MgSO ₄ ). After removing the solvent, the product was purified by chromatography on silica gel, eluting with a 3: 1 mixture of chloroform: petroleum fraction (bp 60-80 ° C). The appropriate fractions containing the product were concentrated and recrystallized from 95% aqueous ethanol to give the final nitrile product as a white crystalline solid.

R = C ₉ H ₁₉ yield = 1.7 g (71%), mp 55.0 ° C. ²⁴ _D ▼ + 55
゜ R = C ₁₀ H ₂₁ O yield = 0.92 g (62%), mp 98.5 ° C ▲ ²⁴ _D ▼ +
6.5 Example 2 Using Route 2 Step 2 (1) Ethyl 4-hydroxybenzoate (0.063 mol) and 2,3-dihydropyran (0.25 mol) in ethyl acetate (80 ml)
To the stirred mixture of l), a saturated solution of hydrogen chloride in ethyl acetate (5 ml) was added dropwise. After the addition, the reaction mixture was stirred at room temperature for 24 hours. The mixture was then washed with a 10% aqueous sodium hydroxide solution (2 × 50 ml), then with water (2 × 50 ml) and finally dried (MgSO ₄ ). After removing the solvent by distillation under reduced pressure, the oily residue was purified by distillation under reduced pressure to obtain a colorless liquid.

Yield = 10.4g (66%) bp120~125 ℃ / 0.1mmHg ( short path distillation) step 2 (2) C ₂ H ₅₀ H (50 ml) the product of Step 2 (1) in (0.03
8 mol) in a solution of potassium hydroxide (0.07) in water (10 ml).
6 mol) was added. The mixture was heated under reflux for 3 hours. While cooling, the solvent was removed by distillation under reduced pressure. Ice water (100 ml) was added to the residue, and the mixture was vigorously stirred at 10 ° C.
While cooling, a 50% aqueous hydrochloric acid solution was added until the acidity of the mixture was about pH3. The product was treated with ethyl acetate (2 ×
100 ml), and the combined organic extracts were extracted with water (2 x 100 m
Washed with l) and dried (MgSO ₄ ). After removal of the solvent, the crude material was crystallized from a 2: 1 toluene: petroleum fraction (bp 80-100 ° C.) to give carboxylic acid as white crystals.

Yield = 5.8 g (69%), decomposed when heated to 145 ° C. Step 2 (3) This step uses the carboxylic acid prepared in Step 2 (2), and uses Step 1 (2) (for the lactate α-hydroxy group). Esterification) was performed in an analogous manner using the product of Step 1 (1) (benzyl ester of S-(+)-lactic acid). The product obtained by column chromatography was used for the next step without further purification.

The melting point of the product is 20 ° C. or less; ▲ [α] ²⁴ _D ▼ + 180 Step 2 (4) Water (8 ml) is added to the product (0.0156 mol) of Step 2 (3).
Add a solution of oxalic acid (0.0031mol) in the mixture to relax the whole.
Refluxed for hours. The solution was cooled and the solvent was removed by distillation under reduced pressure. The residue was heated with water (50 ml), the product was extracted into ether (2 × 50 ml), and the combined ether extracts were washed with water (50 ml) and dried (MgSO ₄ ). (T
The oily crude product (single spot on ic) was used for step 2 (5) without further purification.

Yield = 4.5 g (95%); ▲ [α] ²⁴ _D ▼ + 15 ゜ Step 2 (5) Similar to that used in Step 1 (2), but 4
This step was performed using the DCC esterification method using the phenol product of step 2 (4) instead of benzyl lactate for esterification with -R-biphenyl-4'-carboxylic acid.

R = C ₉ H ₁₉ O; C104 ゜ (S _C 90 ゜) S _A 133.5 ゜ Ch135.5 ゜ I ▲ [α] ²⁴ _D ▼ + 6.9 ゜ Step 2 (6) This step is Step 1 (3) , 1 (4) and 1
Three separate steps similar to (5) ((a), (b)
And (c) below). The characteristics of the product of each of these separate steps for R = C ₉ H ₁₉ O are as follows: (a) C149S _A 198I; ▲ [α] ²⁴ _D ▼ +17.6 ゜ (b) C180S _A 189I; ▲ [α] ²⁴ _D ▼ + 15.0 ゜ (c) C121S _C 132S _A 181I; ▲ [α] ²⁴ _D ▼ -2.3 ゜ Example 3 Step 3 (1) (See Stocker J Org Chem 27 , 2288, (1962)) Until hydrogen uptake is completed, methanol (70 ml)
L in - (+) - mandelic acid (10 g), a mixture of acetic acid (1 ml) and _{5% Rh / Al 2 O 3} (1.95g) was stirred under hydrogen (30 atm). The catalyst was filtered off and the solvent was removed. Recrystallization from carbon tetrachloride gave the cyclohexyl compound as a white crystalline solid.

Yield = 85%; mp = 128 ° C. Step 3 (2) (see SS Wang J-Org-Chem, 41 , 3258 (1976)) A minimal amount of the product of step 3 (1) in 4: 1 ethanol: water ( 5g) solution with cesium carbonate aqueous solution (20% w / v)
And titrated to pH 7. The solution was then evaporated to dryness and co-distilled with sodium-dried benzene (2 × 100 ml) to remove last traces of water. The residue was dissolved in sieved and dried DMF (100 ml), and benzyl bromide (5.3 g) was added with stirring. Stirring was continued for 12 hours, after which the precipitated cesium bromide was filtered off and the solvent was removed under reduced pressure. Water was added to the residue, and the product was treated with ethyl acetate (100 m
l), and the extract was dried (MgSO ₄ ). Purification by column chromatography on silica gel using 1: 3 ethyl acetate / petroleum fraction (bp 60-80 ° C.) as eluent, followed by recrystallization from petroleum fraction (bp 40-60 ° C.).

Yield = 79%; mp 47 ° C. Step 3 (3) (A Hassner, V Alexanian, Tetrahedron, 46 , 4475 (19
78)) sieve-dried suitable carboxylic acid in dichloromethane (50 ml), in this case n-4-octyloxybiphenyl-4'-carboxylic acid (10 mmol), step 3 (2)
(11 mmol), DCC (11 mmol) and N-PPy (1 mmol)
The solution of l) was stirred while excluding moisture. Next, tlc on silica gel eluting with 2: 1 chloroform: petroleum fraction (bp 60-80 ° C.) was performed. The mixture was filtered off and water (3 × 50 m
l) The filtrate was washed successively with 5% acetic acid (3 × 50 ml) and again with water (3 × 50 ml) and finally dried (MgSO ₄ ). The product (oil) was purified by column chromatography on silica gel, eluting with a 2: 1 chloroform: petroleum fraction (bp 60-80 ° C.) to give the product as a colorless liquid.

Yield = 67%; [[α] ²⁵ _D ▼ + 5.3 ゜ Step 3 (4) A mixture of the product of Step 3 (3) and 5% Pd-c in ethanol (25 ml) was taken up by gas uptake. Until the end
Stir under a hydrogen atmosphere. The catalyst was filtered off and the solvent was removed by distillation under reduced pressure. The crude product was purified by silica gel column chromatography eluting with 5: 1 chloroform: methanol. Recrystallization from a petroleum fraction (bp 60-80 ° C.) provided the carboxylic acid as a white crystalline solid.

Yield = 86%; mp = 83 ° C .; ▲ [α] ²⁵ _D -39.5 ゜ Step 3 (5) In a mixture of sodium-dried benzene (25 ml), oxalyl chloride (0.25 g) and DMF (1 drop) Step 3 of
(4) The product suspension of (0.5 g) was stirred for 2 hours. The solvent was removed by distillation under reduced pressure and the residue was dissolved in dry diglyme (50 ml). An aqueous ammonia solution (d = 0.88, 10 ml) was added to this solution with vigorous stirring for 30 minutes, and stirring was continued for another 30 minutes. Mixture with water (100ml)
And the precipitated amide was filtered off. Recrystallization from 4: 1 ethanol: water gave the product as a white powder.

Yield = 82%; mp 126 ° C. Step 3 (6) A solution of the product of Step 3 (5) (0.47 g), thionyl chloride (1.2 g) and dry DMF (30 ml) was stirred for 8 hours. Then the reaction mixture was poured into water (50 ml) and the nitrile was extracted into ether (3 × 50 ml). The ether extract was washed with saturated sodium bicarbonate solution and dried (Mg
SO ₄ ). The crude product was purified by column chromatography on silica gel, eluting with a 1: 5 ethyl acetate: petroleum fraction (bp 60-80 ° C.). Recrystallization from 4: 1 ethanol: water gave the nitrile as a white crystalline solid.

Yield = 78%; mp 58.5 ° C; ▲ [α] ²⁵ _D ▼ -10.5.

Example 4 Ferroelectric smectic liquid crystal mixture containing a compound of formula I in a host which is a compound of formula 4.1.

Mixture A: Transition temperature; S _? ca .40 S _C 66.8 S _A 111.8N 134.7I Ferroelectric properties: Estimated pitch of S _C phase of the mixture was 0.201Myuemu.

Mixture B: Host: same host mixture as Mixture A and 10% by weight Transition temperature: S _? 45 S _C 56.1 S _A 115N 134.8I Ferroelectric properties: Estimated pitch of S _C phase of the mixture was 0.201Myuemu.

Each of the following mixtures C-G has the composition: Based on a smectic host.

Mixture C: 90% by weight host mixture 10% by weight Transition temperature: S _C -S _A 64 ゜, S _A -Ch 109.6 ゜, Ch-I 135.2 to 136.8 ゜ (S _C
Room temperature) Ferroelectric properties: Mixture D: 90% by weight host mixture 10% by weight Transition temperature: S-S _C 32 ゜, S _C- S _A 81 ゜, S _A- Ch118.8 ゜, Ch-I139.2 ~
140.5 ゜ Ferroelectric properties: Mixture E: 60% by weight host mixture Transition temperature: S-S _C 11 ゜, S _C -S _A 58.7 ゜, S _A -N100 ゜, Ch-I124 ~ 12
5.4 ゜ Ferroelectric properties: Mixture F: 75% by weight host mixture Transition temperature: S _C -S _A 62.5 ゜, S _A -Ch 81.4 ゜, Ch-I 121 ~ 123.2 ゜ (room temperature S _C ) Ferroelectric properties: Mixture G: 61% by weight host mixture In this mixture, the two optically active compounds induce the appearance of a Ch phase in the direction of the opposite helical twist, and thus the mixture is pitch compensated.

Transition temperature: S _C -S _A 63.4 ゜, S _A -N 84.2 ゜, N-Ch100 ゜, Ch-I 120.4 ~
122.2 ゜ (room temperature S _C ) Ferroelectric properties: Example 5 Step 4 (1) Stir L-valine (30.0 g, 0.256 mol) in 0.5 M sulfuric acid (390 ml) for 3 hours while maintaining the temperature between 0 ° C. and −2 ° C. To the cooled solution was added sodium sulfite (2 ml) in water (105 ml).
(6.4 g, 0.384 mol) of a cold solution was added dropwise. The reaction mixture was kept stirring at room temperature overnight, then the pH was adjusted to 6 by adding solid sodium bicarbonate. Approximately 150m of the solution under reduced pressure at 50 ° C
Concentrated to l. The solution was acidified to pH 3 with 40% H ₃ PO ₄ and the crude product was extracted into THF (2 × 200 ml). The THF solution was washed with brine, dried (MgSO ₄ ) and concentrated under reduced pressure at 50 ° C. to an oil.

The crude product was taken up in water (105 ml) and decolorized with activated carbon at room temperature. To the cold solution adjusted to pH 4.5-5, a concentrated sodium hydroxide solution was added dropwise. Acetone (3 volumes of aqueous solution) was added and the precipitate formed was filtered off and dried (CaCl ₂ under vacuum).

Yield = 22 g (61%); ▲ [α] ²⁴ _D ▼ = -13.95 ゜ (H
₂ O).

Step 4 (2) Step 4 (1) product (10.0 g, 72 mmol), benzyl bromide (12.2 g, 72 mmol) and sieve-dried DMF (120 m
The mixture of l) was stirred at room temperature for 24 hours. Under reduced pressure (50-55
C), remove the DMF and remove the remaining suspension in ether (100 ml).
And filtered. The filtrate was washed successively with water, sodium bicarbonate solution and water, and dried (MgSO ₄ ). After evaporation of the solvent (55 ° C. or lower), a crude product was obtained.

Yield = 14.4 g (96%) The crude product was purified by distillation at 135-140 ° C./0.6-0.65 mmHg.

Step 4 (3) 4'-octyloxy-4-carboxylic acid (10.8 g, 0.33 mol) in sieved and dried dichloromethane, the product of step 4 (2) (6.9 g, 0.033 mol) and N-PPy (0.
To a stirred mixture of 49 g, 0.033 mol) was added a solution of sieved dried DDC (17.5 g, 0.036 mol) in dichloromethane over 20 minutes.

The reaction mixture was stirred at room temperature for 6 hours. The N, N-dichlorohexylurea was filtered off, and the filtrate was washed successively with water, 5% aqueous acetic acid and water, and finally dried (MgSO ₄ ). After removing the solvent, 4: 1 dichloromethane: light oil (bp 60 to 80) was used as eluent.
The composition diester was purified by silica gel column chromatography using ゜) to obtain a viscous liquid product.

Yield = 12.5 g (74%) Step 4 (4) The product of step 4 (3) (12.5 g, 24.2 mmol) was dissolved in ethyl acetate (160 ml) and 5% Pd on charcoal (200 mg) was added. . The mixture was stirred under a hydrogen atmosphere overnight (the reaction was monitored by TLC). After completion of hydrogenolysis ( ca 550ml
H ₂ ), the catalyst was filtered off and the filtrate was evaporated to dryness to give a solid product. The solid showed a single spot on TLC and was used without further purification.

Yield = 9.7 g (95%); mp = 80-83 ° C. Step 4 (5) The carboxylic acid from step 4 (4) (9.4 g, 22.06 mmol)
l) Oxalyl chloride (5.75 g, 44 mmol) in sodium dried benzene (25 ml) and sieve dried DMF
(2 drops) and reacted for 3 hours at room temperature to convert first to acid chloride. Excess oxalyl chloride and dissolution were removed by distillation under reduced pressure. Composition acid chloride diglyme (10ml)
Dissolved in water and stirred with an aqueous solution of ammonia (5 g = 0.8
8,100 ml). After the addition, the reaction mixture was stirred at room temperature for 30 minutes, then the product was filtered off, washed with water and dried (CaCl ₂ under vacuum).

Yield = 9.4 g (100%); mp = 95-97 ° C. Step 4 (6) Step 4 (5) in sieve dried DMF (100 ml)
To a vigorously stirred solution of the amide from (9.0 g, 22.1 mmol) from was added dropwise over 30 minutes a mixture of thionyl chloride (26.3 g, 221 mmol) and sieve-dried DMF (100 ml). After the addition, the reaction mixture was kept stirring at room temperature for 8 hours, then poured onto ice-water and the product was extracted into ether (2 × 300 ml). The ether extract was washed successively with saturated sodium bicarbonate solution and water, and then dried (MgSO ₄ ). After removal of the solvent, the product was purified by silica gel column chromatography, eluting with 1: 3 ethyl acetate: light oil (bp 40-60 ° C.).

Yield = 8.3 g (97%) The product from the column was recrystallized from light oil (bp 40-60 ° C) to give a white crystalline solid.

mp = 66.9 ° C .; ▲ [α] ²⁰ _D ▼ = -3.1 ゜ (CHCl ₃ ) Suitable carboxylic acid of Step 4 (3) and Step 4
The following compounds were produced by the same method using the amino acids shown in (1).

Example 6 Using Route 6 Step 6 (3) 4-n-decyl-4'-hydroxybiphenyl (0.02 mol) in acetonitrile (100 ml), sieved with vigorous stirring for 20 hours, tosyl lactate (0.024 mol
l) and anhydrous potassium carbonate (0.024 mol) were gently refluxed. Pour the cooled reaction mixture into cold water (200 ml),
Extracted into ether (2 × 150 ml). The ether extracts were combined, combined with water (100 ml) and a cold 5% aqueous NaOH solution (100 m
l), washed with water (2 × 100 ml) and dried (MgSO ₄ ).
After removal of the solvent, recrystallization of the solid residue from 95% aqueous ethanol gave the product as colorless crystals.

Yield = 5.5 g (67%); mp = 38 ° C .; ▲ [α] ²⁴ _D ▼ + 19.1 ゜ (CHCl ₃ ) Step 6 (4) Step 6 (3) product (0.012 mol), water (15 ml) )
KOH (0.0144 mol) and ethanol (50 ml) therein were refluxed moderately for 1 hour. Remove the excess solvent under reduced pressure, dilute the residue with cold water (50 ml), then dilute HCl until pH ~ 2
Was carefully acidified. Mix the mixture with ether (3 ×
(50 ml), the combined ether extracts were washed with water (50 ml) and dried (MgSO ₄ ). After removal of the solvent, the solid residue was recrystallized from petroleum ether (80-100 ° C).

Yield = 4.3 g (93%); mp = 110.5 ° C; ▲ [α] ²⁴ _D ▼ + 8.4 ゜ (CHCl ₃ ) Step 6 (5) Performed in the same manner as in Step 4 of Route 1. Starting materials were the product of Step 6 (4) (0.011 mol), oxalyl chloride (0.021 mol) in benzene (60 ml), DMF (2
Drops) and 35% aqueous NH ₃ in Jigril (100 ml). The crude product was crystallized from petroleum ether (100-120 ° C).

Yield = 3.6 g (88%); mp = 171 ° C. Step 6 (6) Performed in a similar manner to Step 5 of Route 1. Starting materials were the product of step 6 (5) (0.0087 mol) and DMF (80
ml) of thionyl chloride (0.0087 mol). The crude product was chromatographed on silica gel and eluted with CH ₂ Cl ₂ . The purified material was crystallized from ethanol.

Yield = 2.6 g (84%); mp 66 ° C .; ▲ [α] ²⁴ _D ▼ + 96.8 ゜ (CHCl ₃ ) Example 7 The following compound was also prepared using the method outlined above: Some of their properties are shown below.

A. Solid-isotropic 84.3 ゜, ▲ [α] ²⁰ _D ▼ -23.1 ゜ (CHC
l ₃ ) B. Solid ¹ -Solid ² 29.4 ゜, Solid-Isotropic 32.2 ゜ ▲ [α] ²⁰ _D ▼-4.8 ゜ (CHCl ₃ ) C. Liquid, mp -20 ° C or lower ▲ [α] ²⁰ _D ▼ -16.8 ゜ (CHC
l ₃₎ D. Solid -S _C 102 °, S _C -S _A 145 °, the S _A -I154.6 ▲ [α] ²⁰ _D ▼ -9.35 ° (CHCl ₃₎ The compound of Example 8 Formula I and 4.1 Containing ferroelectric smectic liquid crystal mixture. In the following data, substance H1 has the following composition: And the nematic substance E7 has the composition: have.

The properties of the mixture containing the compound of formula I and H1 are shown in Tables 5 and 6. In the table, the following symbols and abbreviations were used.

Spontaneous decomposition of P _S = estimated _{^{(nCcm -2) N * P =}} E7 in chiral nematic pitch ([mu] m) of ^{_{pP S = N * P × P}} S SOP / SON = N * direction of the helical pitch and ^S _{* C} phase The polarizations C ₉ , C ₉ O, etc. are abbreviations of C ₉ H ₁₉ , C ₉ H ₁₉ O, etc.

Table 6 below lists the following substances: 9 shows the properties of a fast-switching ferroelectric smectic liquid crystal mixture based on.

In Table 6, the proportion of the host and the like is expressed in weight%, the phase transition is shown in ° C., the slope is shown in Δ, PW means the minimum pulse width (μs) for switching, and AC means the peak voltage for latching. I do. P _S and the inclination is of 25 ° C..

Table 6 shows the rapid switching time of the mixture due to the low value of the minimum pulse width for switching.

Figure 7, for various mixtures shown in Table 6, shows a P _S graph for temperature (° C.). The symbols in Table 6 correspond to those in the graph.

Example 9 Ferroelectric smectic liquid crystal mixture containing a compound of formula I and 4.3.

composition: A smectic host H2 having the following formula was produced.

Mixture H Was phase transition ^{(℃) I128 N * 84 S} A 64 S * C <-20.

Mixture I The configuration of the two optically active compounds was chosen to induce the appearance of a chiral smectic phase in the opposite helix twist direction.

The phase transition (° C) of the mixture is I145 N ^* 114S _A 59.7 S ^* _C 10S _? Met.

An example of the use of a compound of Formula I in a liquid crystal material and device embodying the present invention will now be described with reference to FIG.

In FIG. 8, the liquid crystal cell is sandwiched between a glass slide 2 having a transparent conductive layer 3 of, for example, tin oxide or indium oxide on its surface, and a glass slide 4 having a transparent conductive layer 5 on its surface. And a liquid crystal material layer 1 exhibiting a chiral smectic phase. The slides 2, 4 having the layers 3, 5 are each coated with a film 6, 7 of a polyimide polymer. Before constructing the cells, films 6 and 7
In a given direction. The rubbing direction is parallel to the cell configuration. The spacers 8, for example of polymethyl methacrylate, separate the slides 2, 4 by the required distance, for example 5 microns.

Fill the space between slides 2, 4 and spacer 8,
The liquid crystal material 1 is introduced between the slides 2 and 4 by sealing the spacer 8 under vacuum in a known manner. The liquid crystal material is smectic A, nematic or isotropic (obtained by heating the material) when introduced between slides 2, 4 to promote alignment of the liquid crystal molecules in the rubbing direction on slides 2, 4 It is preferably a liquid crystal.

The polarizer 9 has a polarization axis parallel to the rubbing direction of the films 6, 7, and the analyzer (crossed polarizer) 10 has a polarization axis perpendicular to the rubbing direction.

As described above, applying a square wave voltage (from a conventional source, not shown) varying between about +10 volts to -10 volts by contacting layers 3 and 5 across the cell. As described above, the cell switches quickly upon a change in the voltage signature between dark and bright states.

In another device (not shown) based on the cell structure shown in FIG. 8, the layers 3 and 5 may be formed in a known manner, for example by photoetching or deposition through a mask, for example by means of one or more indicia, For example, letters, numbers, words or figures and those commonly found on displays may be provided and selectively shaped. Thereby, the formed electrode part is processed by various methods including various operations.

The liquid crystal substance 1 may be any one of those described in the above embodiments.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code Agency reference number FI Technical indication location C07C 255/41 C07C 255/41 C09K 19/12 9279-4H C09K 19/12 19/14 19/14 19/20 19/20 19/30 19/30 G02F 1/13 500 G02F 1/13 500 // C07M 7:00 (72) Inventor Toyn, Kennes Jillson North Humberside HH, UK・ 6.8 Kew Dublie, Haar, Hall Road ・ 25 (72) Inventors Scrowston, Richard Mikle United Kingdom, North Hambarside, Beverly, Walkington, Thornes Croft 11 (72) Inventor Jackson, Adam North Humbarside HU・ 6 Kew Tay, Harl, Analby Road, Day La Paul Avenue 10 (72) Inventor Cyan, Lawrence Comeming Mining UK, North Humbarside, Haar, Holderness Road, Lee Street 112 (72) Inventors Shienoda, Ibrahim Jindey, United Kingdom, North Humbarside H. U. 52 E. Daville, Harl, Newland Avenue, Trenton Street, 13 (72) Inventor Brad de Cillo, Madalin Jiyoun Gloucester GL 18.1E J.E., United Kingdom, Near Nuent, Atupredon, "Underleaf" (no address) (72) Inventor Brimmel , Victoria United Kingdom, Worcestershire Dublin Ruth Kloom, Keyrain Cottage (No Address) (72) Inventor Constant, Dienifaer, Worcestershire, Powysk, Bowling Green Road 8 (72) Inventor Raines, Edward Peter, Worcestershire, UK・ Double Ale 14.2 ETEX TAY, Mall Burn, Hall Green, Reydon Rawd 23 (56) References JP-A-61-243055 (JP, A)

Claims (18)

(57) [Claims] 1. The formula: [Wherein X is a general formula: (Where R is hydrogen, C ₁ -C ₁₂ alkyl or alkoxy, Are the same or different and are each independently phenyl, halogen-substituted phenyl or trans-cyclohexyl; A is a single bond, COO or OOC;
Is 0 or 1), Y is selected from COO or O, B is alkyl having 1 to 12 carbon atoms, cyclohexyl or Wherein d is 0 or 1, and R ′ is a group selected from hydrogen, C ₁ -C ₁₂ alkyl or alkoxy.] An optically active compound represented by the formula: Where i) an intermediate value when a is 1 Is halogen-substituted phenyl; ii) Y is O; iii) B is cyclohexyl; iv) B is (B) the compound having the formula: Wherein i) a is 1; ii) Y is O; iii) B is cyclohexyl; iv) B is V) B is a C ₃ -C ₁₂ branched alkyl, wherein at least one of the following is satisfied: (2) -Y-CH (CN) -B is -COOCH (CN) -B
The compound of claim 1, wherein 3. The compound according to claim 2, wherein B is n-alkyl. (4) B is a structural formula of B ¹ (In the formula, t is 0 or an integer of 1 to 6, and n and m may be the same or different and each take a value of 1 to 6.)
3. The compound according to claim 2, which is a branched or optically active alkyl group. 5. The compound according to claim 4, wherein t is 0 or 1, and at least one of n and m is one. 6. The compound according to claim 2, wherein B is cyclohexyl. 7. A structural formula: (Wherein, R ₁ is n- alkyl or n- alkoxy C ₃ ~C _12, R ₂ is a is a branched or optically active alkyl group of structure B ¹⁾ compound of claim 4 with. 8. The structural formula: (In the formula, R ₁ is C ₃ is n- alkyl or n- alkoxy -C ₁₂₎ The compound of claim 6 with. 9. A structural formula: (Wherein, R ₁ is n- alkyl or n- alkoxy C ₃ ~C _12, R ₂ is a is n- alkyl C ₁ -C ₁₂₎ The compound of claim 3 having. 10. The structural formula: (Wherein, R ₁ is n- alkyl or n- alkoxy C ₃ ~C _12, R ₂ is a is a branched or optically active alkyl group of structure B ¹⁾ compound of claim 4 with. 11. A structural formula: (In the formula, R ₁ is C ₃ is n- alkyl or n- alkoxy -C ₁₂₎ The compound of claim 6 with. 12. The following structural formula: Wherein R ₁ is C ₃ -C ₁₂ n-alkyl or n-alkoxy, and R ₂ is C ₁ -C ₁₂ n-alkyl or C ₃ -C ₁₂
Selected from branched or optically active alkyls). 13. A structural formula: Wherein R ₁ is C ₃ -C ₁₂ n-alkyl or n-alkoxy, and R ₂ is C ₁ -C ₁₂ n-alkyl or C ₃ -C ₁₂
Selected from branched or optically active alkyls). 14. R ₂ is _{CH 3, C 2 H 5,} C 3 H 7, n-C 4 H 9, n-C
_{5 H 11, n-C 6} H 13, n-C 7 H 15, CH (CH 3) 2, CH 2 CH (CH
_{3) 2} or CH (CH ₃₎ is selected from C ₂ H _5, R ₁ is C ₈ -C ₁₀
The n-alkyl or n-alkoxy of claim 7,8,
15. The compound according to any one of 10, 11, 13 and 14. 15. A mixture of at least two compounds, at least one of which has the formula: [Wherein X is a general formula: (Where R is hydrogen, C ₁ -C ₁₂ alkyl or alkoxy, Are the same or different and are each independently phenyl, halogen-substituted phenyl or trans-cyclohexyl; A is a single bond, COO or OOC;
Is 0 or 1), Y is selected from COO or O, B is alkyl having 1 to 12 carbon atoms, cyclohexyl or (Where d is 0 or 1 and R ′ represents a group selected from hydrogen, C ₁ -C ₁₂ alkyl and alkoxy). : Where i) an intermediate value when a is 1 Is halogen-substituted phenyl; ii) Y is O; iii) B is cyclohexyl; iv) B is (B) the compound having the formula: Wherein i) a is 1; ii) Y is O; iii) B is cyclohexyl; iv) B is It is; v) B is C ₃ is branched alkyl of -C _12; ferroelectric smectic liquid crystal material characterized in satisfying at least one of it. 16. The following formula: 17. The composition according to claim 16, further comprising at least one of the compounds (wherein R ^A and R ^B independently represent a C ₁ -C ₁₂ n-alkyl or n-alkoxy or an optically active alkyl or alkoxy group). Material. 17. The formula: Wherein R ^A and R ^B are independently C ₁ -C ₁₂ n-alkyl or n-alkoxy.
17. The material of claim 16, further comprising: 18. A liquid crystal electro-optical display comprising a ferroelectric smectic liquid crystal material, wherein said liquid crystal material comprises a mixture of at least two compounds, at least one of which has the formula: [Wherein X is a general formula: (Where R is hydrogen, C ₁ -C ₁₂ alkyl or alkoxy, Are the same or different and are each independently phenyl, halogen-substituted phenyl or trans-cyclohexyl; A is a single bond, COO or OOC;
Is 0 or 1), Y is selected from COO or O, B is alkyl having 1 to 12 carbon atoms, cyclohexyl or (Where d is 0 or 1 and R ′ represents a group selected from hydrogen, C ₁ -C ₁₂ alkyl and alkoxy). : Where i) an intermediate value when a is 1 Is halogen-substituted phenyl; ii) Y is O; iii) B is cyclohexyl; iv) B is (B) the compound having the formula: Wherein i) a is 1; ii) Y is O; iii) B is cyclohexyl; iv) B is It is; v) B is a branched alkyl of C ₃ -C _12; satisfies at least one of, that the device according to claim.